Challa A, Bevington A, Angier C M, Asbury A J, Preston C J, Russell R G
Clin Sci (Lond). 1985 Oct;69(4):429-34. doi: 10.1042/cs0690429.
A technique is described for the determination of orthophosphate (Pi) in human erythrocytes. The advantages of the technique are that it uses whole blood rather than separated erythrocytes, that it avoids major hydrolysis of organic phosphates, that it takes account of incomplete recovery of Pi and that it minimizes the effects of chilling the cells. In chilled samples from 46 patients in an intensive care unit, the cellular concentration of Pi was proportional to that in plasma. Blood samples from nine normal subjects were incubated at 37 degrees C. The cellular Pi was 0.79 mmol/litre of cells using an external standardization and 0.67 using an internal standardization. When the same cell samples were chilled on ice for 30 min, the internally standardized value decreased further to 0.57 mmol/litre of cells. These results suggest that differences in recovery, and the extent of chilling, contribute to the variability in the previously reported values for erythrocyte Pi. If Pi, like chloride, had distributed passively between cells and plasma in these samples, the cell to plasma molar concentration ratio for Pi should have been 0.29, compared with the measured value of 0.64. This difference suggests that some factor, in addition to passive diffusion, determined the distribution of Pi.
本文描述了一种测定人体红细胞中正磷酸盐（Pi）的技术。该技术的优点在于它使用全血而非分离的红细胞，避免了有机磷酸盐的大量水解，考虑到了Pi回收不完全的情况，并将细胞冷却的影响降至最低。在重症监护病房46例患者的冷冻样本中，细胞内Pi浓度与血浆中的浓度成正比。来自9名正常受试者的血样在37℃下孵育。使用外部标准化时，细胞内Pi为0.79 mmol/升细胞，使用内部标准化时为0.67。当相同的细胞样本在冰上冷却30分钟时，内部标准化值进一步降至0.57 mmol/升细胞。这些结果表明，回收率和冷却程度的差异导致了先前报道的红细胞Pi值的变异性。如果Pi像氯离子一样在这些样本的细胞和血浆之间被动分布，Pi的细胞与血浆摩尔浓度比应为0.29，而测量值为0.64。这种差异表明，除了被动扩散外，还有一些因素决定了Pi的分布。
